i sail alot with french speaking bloke in swan river[i thought it was you] he sails starboard formula with 11.0m severne cr2. he does plane earlier than me although not that much.he is tall/very slim, low 70kg.when he first noticed i was sailing only 7.7 he said i thought you were on at least a 9.0m.
i believe this guy planes in around 7/8knots. i will ask him. i plane i think in 8/9knots.
open to possibility i could be way off mark.

other day sailed in 25/35 knots[seabreeze.com.au] with 5.0m ,tons of downhaul. i sail sheeted in only in lulls.upwind and sheeted out in gusts.
a guy on shore had wind metre max gust he recorded was 32knots. it was clearly stronger out further.

Watching for the formation of white caps is clearly a no compromise way of checking wind speed. Small caps begin to form at 10 knots. In either protected or open water, caps still begin to form at 10 knots, just different sizes.

Where I sail, it's protected near shore so I frequently use binoculars to check the wind further out in the lake to see what is really happening. Our winds aren't steady so as a general rule, I don't go out unless I see a few white caps (6-12 knot winds), and then it's with a formula board and an 11.0 to get planing. I weigh 78 kg. I am also very good in light winds, usually on much smaller sails than my competition when racing formula.

Mac, to plane in 8-9 knots on your gear, you would have to pump you brains out to get going. How much are you pumping? Baggy sails don't pump well, so by reducing outhaul and downhaul, it makes pumping much less effective.

2 people with same weight/equip can plane at different thresholds.tuning out/downhaul relative to conditions present can make a big difference.
i have always had a knack of planing quickly, holding 7m plus sails[sheeted in] in even moderate wind is the downside to this.
i dont take your point of baggy sails been harder to pump onto plane. this may be true but in such light wind a full sail overall will plane for me anyway much faster than rigging with manufactures specs on out/downhaul.
i had my 7.7m on my f2 x/speed 64cm wide last week i was been outplaned by guy with new2010 sonic[68wide] with 7.8m pryde racing sail. i changed boards to much larger fanatic and was planing way way earlier than he was.
i now only rig my 7.7m on my largest board after this experience.
strangely my 5.8m om my f2 64wide seems to plane almost as quickly as when i put 7.7m on it.
i weighed my fanatic falcon its specs are 275x75,it weighs including fin,straps between 8.5/8.75kg,so for size is ulta/light.
will closely monitor wind on light days on seabreeze.com.au when sailing in future.

Hi Mac 33, a few sail models have been launched recently (NP Helium, Severne Glide) with increased planning ability in light winds. These sails are baggy by design and you can't really flatten them, resulting in little gust tolerance. According to NP a 7.5 Helium has same planning threshold than a 8.5+ regular V8. At your weight you may very well plane around 9/10 Knts with your baggy 7.7 and Falcon (pointing efficiently upwind is another story). I'm more surprised by your performances with 5.8 and 5 sqm. Those are quite small by actual standards, at least for freeride/slalom. OK I like some more power in sail but at similar weight I would not take a 5.8 for wind below 15/16 Knts, 20 Knts for the 5. Something must be wrong either with your windspeed or weight measurements;-)

sailed today on 5.8m in exactly that wind and never once off plane on kinetic58. seabreeze website surely cannot be that wrong. sailed 2kms downwind [2/3] legs and [6/7] legs to get upwind again.
did not rig to manufactures specs though. twisting off to barely top batten and negative outhaulto max.
this sail tuning is not for everyone. advantages for me,
quicker to plane
planes through lulls better
higher topend speed through lulls
higher pointing angle due to less downhaul.

Planing in 15/16 Knots with 5.8 mē, yes it works. Lightweight sailors, kids and ladies do that even with "standard" sail tuning and narrow boards. With a baggy 5 mē, why not if the wind is steady enough. Sails of 15+ years ago (NS Infinity, Tiga Power Slalom) had such low end power. Planning in 12/13 Knts with 5 mē as you started this post? Well, if this copes with your definition of funboard... have fun.

i agree 5.0m in 12/13 knots is not fun.
5.8m on med size board in 15/16 knots for me is ideal.
got caught out using 5.8m a while back in steady 20/22 knots it was hard work and tiring.
had to sail upwind in gusts,had stayed on reach[sheeted in] would have wiped out unquestionably.
was pissed off that day as considered it a half wasted day as dont like to sheet out.
as the song goes
and i did it my way.

It's the other end, but most modern 5.8 sails are pretty manageable in 20/22 Knts for a 67 Kg sailor. If you rig one properly (flat) you can remain sheeted in without being blown away by gusts. Of course it will have less back hand / low end power. This is not a macho thing, just proper rigging for such conditions.

you are right, rigged correctly to manufacture specs of downhaul, say to 4th batten down with at least neutral outhaul i could stay sheeted in mostly in 20/22 knots.
i found from testing with gps that on reach with 5.8m in resonably chop my peak speed was around 29knots. i hardly ever hit 30 with 5.8m no matter what tuning.
with 5.0m i would never fail to get to 30. i found it hard to better this 30 however .
1 knot difference in speed its not much but most drag races i have are very close.
for most 5.8m would be faster in this wind strength than 5.0m, definately not for me.
its all relative to your weight/ strength
my legs/arms are real slim, maybe i need to stop being a vegetarian[15years] in order to make 5.8m work better than 5.0m in this wind strength.
in golf theres a saying it goes its not how its how many.

5.8m on med size board in 15/16 knots for me is ideal.
got caught out using 5.8m a while back in steady 20/22 knots it was hard work and tiring.
had to sail upwind in gusts,had stayed on reach[sheeted in] would have wiped out unquestionably.
was pissed off that day as considered it a half wasted day as dont like to sheet out.

Mac33,

I'm surprised you were risking being wipped out on a reach and it was hard work and tiring in 20/22 knots with a 5.8 m2 sail. This really sounds to me that it was much more windy than you thought. In true 15/16 knots gusting up to 20/22 knots, I had a blast for 6 hours on iSonic 53 speed gun + NP RS1 6.6 m2 sail. At no time was I feared to sheet out in a gust (bad idea in fact), feared from being wipped out or was hard work or tiring. Was I ever pissed off? No way! A perfectly balanced session. And damn' fast : Vmax 29.9 knots. Nice drag racing with a pal on his F2 sputnik + 6.8 m2 sail 100% of the time planing pedal to the metal. Kids, women or freestylers were on 5.4, 5.8 or 6.2 m2 sails and freestyle/freewave/wave boards. They were all planing in 20+ knots gusts whereas the 75+ kg guys on such gear were clearly schlogging in 15 knots lulls, no questions.

My suggestion next time you feel overpowered, tired and pissed off is very simple: set your sail with max downhaul. Outhaul neutral or -1 cm negative is fine for max speed on a broad reach (100-120° angle) without ever thinking of sheeting out. Reason ? The loose leech works properly as designed by the sailmaker for your benefit. You will discover what it really means by sailing in overpowered conditions with a perfectly balanced and tireless sail. Try it ! You'll be surprised... And absolutely no need to change your diet!